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Hip Fractures in Adults with Schizophrenia: A Population-based Evaluation of the Burden and Quality of Care

Abstract

Hip fractures have life-altering consequences. Individuals with schizophrenia may experience a higher likelihood of hip fractures, worse postfracture outcomes, and suboptimal care. This thesis consisted of three distinct population-based studies which aimed to compare the burden of hip fractures, postfracture outcomes, and osteoporosis management among adults with and without schizophrenia in Ontario, leveraging observational study design methods, and multiple individually-linked administrative data sources. Using descriptive epidemiological methods, Study 1 characterized hip fractures in individuals with schizophrenia, by comparing sex-specific age-standardized rates and baseline characteristics to those without schizophrenia over a ten-year period. Analyses suggested that the age of onset for an index hip fracture is earlier among individuals with schizophrenia, particularly men. Annual age-standardized rates were threefold higher in men with vs without schizophrenia, and more than twofold higher in women. Study 2 investigated the association between schizophrenia and short- and long-term outcomes following hip fracture. Age- and sex-adjusted Kaplan-Meier survival curves suggested that individuals with schizophrenia were less likely to survive until 1-year following the index event. Age- and sex-adjusted GEE models suggested that schizophrenia was positively associated with 30-day mortality (OR, 1.31; 95% CI, 1.12-1.54) and readmissions (OR, 1.40; 95% CI, 1.251.56). The positive association between schizophrenia and readmissions (OR, 1.34; 95% CI, 1.20-1.50) persisted in fully adjusted multivariable models. In Fine-Gray competing risk models, schizophrenia was positively associated with subsequent hip fracture within two years (sdRH, 1.29; 95% CI, 1.09-1.53), with male hip fracture patients with schizophrenia sustaining a refracture 50 days earlier. Study 3 compared postfracture osteoporosis management between individuals with and without schizophrenia. Using Fine-Gray models, findings from Study 3 suggested that a schizophrenia diagnosis was associated with a lower incidence of bone mineral density testing and pharmacologic treatment for osteoporosis (sdRH, 0.79; 95% CI, 0.72-0.88), after accounting for important enabling and predisposing factors, and mortality as a competing risk. This thesis contributes important evidence to the sparse literature on hip fractures in individuals with schizophrenia. Findings have implications for fracture prevention, clinical management of bone health, and understanding how to best intervene across the full continuum of multidisciplinary care in order to optimize outcomes for this disadvantaged subpopulation.